Image forming apparatus and power control method

ABSTRACT

A sub-CPU copes with a status obtaining request from a network in a sleep mode. Further, necessary least power control for updating a status in an image forming apparatus in the sleep mode is realized by the sub-CPU.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to an image forming apparatus which isconnected to a network via network connecting means and can execute apredetermined job process and to a power control method.

[0003] 2. Related Background Art

[0004] Hitherto, a system constructed by connecting printers (includinga copying apparatus and a hybrid apparatus) and computers via a networkexists.

[0005]FIG. 16 is a block diagram showing an example of a conventionalnetwork system including an image forming apparatus and corresponds to,for example, a construction of a network system which is used by aplurality of users in a network environment.

[0006] In FIG. 16, the network system is constructed by connecting aplurality of PCs (personal computers) 103 a and 103 b, a plurality ofcopying apparatuses 101 a and 101 b, and a server 102 via a network. Thecopying apparatus (each of the copying apparatuses 101 a and 101 b) isconstructed by a printer unit 231, a reader unit 226, a controller unit232, and a DC power source 203. The controller unit 232 transmits andreceives signals to/from the outside, makes on/off control of the DCpower source 203, and controls the reader unit 226 and the printer unit231 via the network.

[0007] Ordinarily, when the copying operation and the printing operationare not executed for a predetermined time, the copying apparatus entersa sleep mode (power saving mode) in order to save energy.

[0008] Application software to manage the network has been known. Byinstalling such software into the PC, a status of the copying apparatusconnected to the network can be recognized. For example, if absence ofsheets occurs, such a status of the copying apparatus can be displayedon a display screen of the PC. Even if the copying apparatuses 101 a and101 b are in the sleep mode, when there is a print request from the PCconnected to the network, it is detected, the DC power source 203 of thecopying apparatus is activated, and the whole copying apparatus isactivated, thereby performing a print output.

[0009] The foregoing conventional technique, however, has the followingproblems.

[0010] If an inquiry about the latest status of the image formingapparatus, for example, the copying apparatus connected to the networkwhich is always updated is made by the PC when the copying apparatus isin the sleep mode, the controller unit 232 in the copying apparatusactivates the DC power source 203, supplies a power source to alldevices including various sensors in an engine, and detects the inquiredstatus. To detect the status, the controller unit 232 communicates withthe reader unit 226 and printer unit 231 and returns communicationresults to the network.

[0011] Therefore, in spite of the fact that the apparatus is in a stateof the sleep mode in which the energy saving is accomplished, each timethe status of the copying apparatus is inquired, it is necessary tosupply the power source to the whole copying apparatus, or the powersource of the copying apparatus always has to be kept in a currentsupplying mode. Such a situation is contradictory to a recent energysaving purpose.

[0012] A method whereby a current is supplied only to the sensors in theengine in the printer in the power saving mode only in the case wherethere is a status request from the application software for managing thenetwork can be considered. However, it is presumed that under conditionssuch that a plurality of users share the printer, the status requestsare frequently made by the plurality of users, so that a power savingeffect cannot be expected.

SUMMARY OF THE INVENTION

[0013] The invention is made to solve the above problems and it is anobject of the invention to provide a mechanism which can realize powersaving more effective than the conventional one and can make a responseof an updated status to a status request from an external apparatuswithout making the user be aware or execute any tiresome operations.

[0014] It is another object of the invention to provide a mechanism inan image forming apparatus having a plurality of various types ofsensors, wherein a status response to an external apparatus can be madeto a sub-CPU whose electric power consumption is smaller than that of amain chip.

[0015] To accomplish the above objects, there is provided a mechanism inan image forming apparatus which can communicate with an externalapparatus via network connecting means, wherein when an internal statusof the image forming apparatus is updated, control is made so as toperiodically activate a power supply of a power source which isnecessary for the status update and power-saved in a power saving modeand the external apparatus is notified of the status updated inaccordance with such control.

[0016] Or, there is provided a mechanism constructed in a manner suchthat the power source to detecting means is intermittently supplied tothereby allow the detecting means to update the status, when an inquiryabout the status of the image forming apparatus is made by the networkconnecting means when a power control mode is in a normal standby mode,the notification of status information detected before by the detectingmeans is made by first control means, when the inquiry about the statusof the image forming apparatus is made by the network connecting meanswhen the power control mode is in the power saving mode, thenotification based on the status information updated by update controlmeans is made by second control means, and a power supplying state tothe first and second control means is controlled in accordance withwhether the power control mode is in the normal standby mode or thepower saving mode.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a block diagram showing an example of a network systemto which an image forming apparatus showing the first embodiment of theinvention can be applied;

[0018]FIG. 2 is a block diagram for explaining a control construction ofa digital hybrid apparatus shown in FIG. 1;

[0019]FIG. 3 which comprised of FIGS. 3A and 3B is a block diagram forexplaining a construction of a DCON shown in FIG. 2;

[0020]FIG. 4 is a diagram for explaining an interface between acontroller and the DCON shown in FIG. 2;

[0021]FIG. 5 is a diagram for explaining an interface between the DCONand a sensor A group shown in FIG. 2;

[0022]FIG. 6 is a diagram for explaining an interface between the DCONand a sensor B group shown in FIG. 2;

[0023]FIG. 7 is a diagram for explaining a detailed construction of thecontroller shown in FIG. 2;

[0024]FIG. 8 which comprised of FIGS. 8A and 8B is a diagram forexplaining a construction of an RCON shown in FIG. 2;

[0025]FIG. 9 is a diagram for explaining details of an I/F circuit of anoption of a paper feed system shown in FIG. 3;

[0026]FIG. 10 is a diagram for explaining an interface between the I/Fcircuit of the paper feed system option and a sensor B group shown inFIG. 3;

[0027]FIG. 11 is a flowchart showing an example of a first controlprocedure in the image forming apparatus according to the invention;

[0028]FIG. 12 is a flowchart showing an example of a second controlprocedure in the image forming apparatus according to the invention;

[0029]FIG. 13 is a flowchart showing an example of a third controlprocedure in the image forming apparatus according to the invention;

[0030]FIG. 14 is a flowchart showing an example of the third controlprocedure in the image forming apparatus according to the invention;

[0031]FIG. 15 is a diagram for explaining a memory map of a memorymedium for storing various data processing programs which can be readout by the image forming apparatus according to the invention; and

[0032]FIG. 16 is a block diagram showing an example of a conventionalnetwork system including an image forming apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0033] [First Embodiment]

[0034]FIG. 1 is a block diagram showing an example of a network systemto which an image forming apparatus showing the first embodiment of theinvention can be applied. Naturally, image forming apparatuses to whichthe invention can be applied include: a printing apparatus (printer) anda facsimile apparatus using an electrophotographic system or an ink jetsystem or a digital hybrid apparatus for executing compound imageprocesses including a printing process and a facsimile process. Thedigital hybrid apparatus will be described as an example hereinbelow.

[0035] In FIG. 1, reference numerals 101 a and 101 b denote the digitalhybrid apparatuses. As will be explained hereinlater, an electric poweris supplied from the power source 203 to the printer unit 231, readerunit 226, and controller unit 232, so that those digital hybridapparatuses operate.

[0036] Reference numeral 102 denotes the server and 103 a and 103 bindicate the PCs (personal computers) and those apparatuses areconnected by Ethernet (registered trademark) 104 as a local areanetwork. It is possible that the user connects to the PCs 103 a and 103b or the server 102 shown in FIG. 1, receives print jobs from the PCs103 a and 103 b, and outputs status information in response to inquiriesabout statuses which are made by the PCs 103 a and 103 b via theEthernet (registered trademark) 104, respectively.

[0037] The “status” used here indicates an accumulating situation or aprocessing situation of current jobs, size setting of a present sheetcassette, the presence or absence of paper in the sheet cassette, aconnecting situation of an option, or the presence or absence of toner.The digital hybrid apparatus has a facsimile function and is connectedto the outside via a predetermined communication line (for example,telephone line) so that it can communicate.

[0038] In the digital hybrid apparatus, the same constructing portionsas those of a general copying apparatus will be simply explainedhereinbelow. With respect to the operation to read out an image from anoriginal, image data is converted into digital data by using aphotoelectric converting device such as CCD or contact sensor. Withrespect to the printing operation, a latent image is formed onto aphotosensitive material charged at a high voltage by using a laser, animage of toner as a developing material is formed onto the latent image,and it is transferred onto transfer paper.

[0039] The digital hybrid apparatus in the embodiment has two waitingmodes: a standby mode and a sleep mode. In these modes, neither of thecopying operation, the printing operation, the facsimile transmittingoperation, the facsimile receiving operation, the scanning operation,and their compound operation is executed.

[0040] In the standby mode, although the above operation is not executednow, it can be immediately started. In the sleep mode, although theabove operation is not executed now and cannot be immediately started,electric power consumption is smaller than that in the standby mode.

[0041]FIG. 2 is a block diagram for explaining a control construction ofeach of the digital hybrid apparatuses 101 a and 101 b shown in FIG. 1.

[0042] In FIG. 2, reference numeral 201 denotes a control board (DCON).The DCON 201 receives video data from a controller (main control board)202, which will be explained hereinlater, via an interface I/F-1, makesprint control, is connected to sensor groups 208, 209, and 210 necessaryfor various print control via interfaces I/F-2, I/F-3, and I/F-4, isconnected via an interface I/F-5 to a DC load group 211 for printing, isconnected via an interface I/F-6 to units 212 regarding a laser forexposing the photosensitive material, and controls those componentdevices, respectively.

[0043] The DCON 201 is connected via an interface I/F-7 to a paperdelivery option 213 for sorting, is connected via an interface I/F-18 toa paper feed option 214 for increasing the number of sheet cassettes forpaper feed, and controls various information by serial communication,respectively.

[0044] The sensors are classified into three groups: the sensor A group208 for periodically detecting in the sleeping state as well as in astate during the copying/printing operation or in a standby mode; thesensor B group 209 for detecting in more detail in the sleep mode aswell as in the state during the copying/printing operation and in thestandby mode in accordance with statuses of the sensor A group if it isdetermined that the detection is necessary; and the sensor C group 210for detecting only in the state during the copying/printing operationand in the standby mode but never performing the detection in the sleepmode.

[0045] The DCON 201 is connected via the interface I/F-7 to an AC driver205, which will be explained hereinlater, and controls an AC load group215 connected after the AC driver 205. A heater (not shown) for heatingand fusing the toner and fixing it onto the sheet is included in the ACload group 215. With respect to the power supply to the DCON 201, thepower source which is supplied only in an operative mode and the standbymode is supplied from the DC power source 203 via PW-DC-2, and the powersource which is supplied also in the sleep mode is supplied from thecontroller 202 via the interface I/F-1.

[0046] The AC driver 205 applies an AC voltage of 100V to the AC loadgroup 215. In this case, the current supply and non-current supply of AC100V to the AC load group 215 are switched by a switching device such astriac or SSR via PW-AC-3 in response to an on/off signal which issupplied from the DCON 201 via the interface I/F-7.

[0047] Reference numeral 216 denotes a control board (RCON) whichcontrols a scanner system, is connected via interfaces I/F-12, I/F-13,and I/F-14 to an image sensor for reading the image and sensor groups217, 218, and 219 for controlling the original paper, is connected viainterface I/F-15 to a DC load group 220, and controls those devices,respectively.

[0048] The sensors connected to the RCON 216 are also classified intothree groups: the sensor D group 217 for periodically detecting in thesleeping state as well as in a state during the copying/printingoperation or in a standby mode; the sensor E group 218 for detecting inmore detail in the sleep mode as well as in the state during thecopying/printing operation and in the standby mode after the sensor Dgroup changes; and the sensor F group 219 for detecting only in thestate during the copying/printing operation and in the standby mode butnever performing the detection in the sleep mode.

[0049] Reference numeral 221 denotes an image sensor for converting theimage into an electric signal. The image sensor 221 converts a format ofthe electric signal into a predetermined format and transfers the videodata to the controller 202, which will be explained hereinlater, viainterfaces I/F-16 and I/F-9.

[0050] Reference numeral 202 denotes the main control board (controller)which is connected to the DCON 201 via the interface I/F-1 and isconnected to the RCON 216 via the interface I/F-9. By this connection,in the copy mode, the video data of the original is sent from the RCON216 to the controller 202. After the video data is processed, it is sentfrom the controller 202 to the DCON 201. At this time, in the controller202, processes for converting a format of the video data, modifying thevideo data, and matching transfer timing of video data with timing ofthe printer are executed. The controller 202 is connected to anoperation unit 222 via an interface I/F-19 and can receive an input fromthe operator and display a necessary message to him. Reference numeral223 denotes a power switch. An input signal from an interface I/F-20becomes a trigger for shift to the sleep mode or recovery from the sleepmode to the standby mode.

[0051] The controller 202 is also connected to the DC power source 203via the interface I/F-8 and can control the turn-on/off of a partial DCpower output included in PW-DC-1, PW-DC-2, and PW-DC-3. The controller202 is connected to a FAX-UNIT 206 via an interface I/F-11 and connectedto a telephone line after the FAX-UNIT 206. The controller 202 isconnected to a LAN-UNIT 207 via an interface I/F-10 and connected to theEthernet (registered trademark) after the LAN-UNIT 207. The LAN-UNIT 207is not limited to the Ethernet (registered trademark) but presumed to bea communication unit according to a predetermined protocol. Naturally,both of a wireless manner and a wired manner can be applied.

[0052] Reference numeral 204 denotes an AC input unit. An AC voltage of100V is inputted from a power outlet to the AC input unit 204 via a pathof PW-AC-1 and the AC input unit 204 supplies the AC voltage of 100V tothe DC power source 203 and AC driver 205 via a path of PW-AC-2 througha circuit for detecting an electric leakage, an XCON for removingnoises, or a circuit such as a discharging resistor or the like of theXCON. The image sensor 221 is a sensor for reading the image.

[0053]FIGS. 3A and 3B are block diagrams for explaining a constructionof the DCON 201 shown in FIG. 2. In FIGS. 3A and 3B, the same andsimilar component elements as those in FIG. 2 are designated by the samereference numerals.

[0054] In FIGS. 3A and 3B, each of P5VB and P5VC denotes a power sourceof 5V. P5VB denotes the power source which is supplied from the DC powersource 203 in the state during the copying/printing operation and in thestandby mode. Reference numerals 301 to 309 denote interface circuits(I/F circuits).

[0055] The controller 202 controls the DC power source 203 so as to turnon or off P5VB. P5VC denotes the power source which is supplied from thecontroller 202 via the interface I/F-1. P5VC is always held in the ONstate in the state during the copying/printing operation and in thestandby mode. In the sleep mode, P5VC is turned on only when it isnecessary.

[0056] The timing when it is necessary in the sleep mode is timing whenthe controller uses a parallel/serial (P/S) conversion unit Q302 and aserial/parallel (S/P) conversion unit Q303 and detects the sensor Agroup 208 and the sensor B group 209. P5VC is on/off controlled by thecontroller 202.

[0057] Q301 denotes a microcomputer which has at least a ROM and a RAMtherein and operates in accordance with programs written in the ROM. Oneof roles of the microcomputer Q301 is monitoring of the status. Themicrocomputer Q301 detects the sensor A group 208 and the sensor B group209, which will be explained hereinlater, at input ports and notifiesthe controller 202 (to a main CPU or a sub-CPU) of informationindicative of the opening/closure of a door, an opening/closure state ofthe cassette, a sheet size, and the presence or absence of the sheets asparts of statuses by the serial communication of the interface I/F-1.

[0058] Another main role of the microcomputer Q301 is the control of theprint. The microcomputer Q301 detects statuses of input ports connectedto the sensor A group 208, sensor B group 209, and sensor C group 210,on/off controls the DC load group 211 and the AC driver 205 at outputports connected to the DC load group 211 and output ports connected tothe AC driver 205, and makes conveyance control of the sheet,high-voltage control, fixing heater control, and the like.

[0059] Q309 denotes a gate array which receives the video data from theinterface I/F-1, controls the units 212 regarding the laser via the I/Fcircuit 308 and the interface I/F-3, exposes the photosensitive material(not shown) by the laser on the basis of the video data, and forms alatent image as a distribution of a charging state onto thephotosensitive material. The microcomputer Q301 writes set values formaking the gate array Q309 operative via a bus.

[0060] As signals of the serial communication from the interface I/F-1,there are: SDATA_C2D as a serial data signal which is sent from thecontroller 202 to the DCON 201; SDATA_D2C as a serial data signal whichis sent from the DCON 201 to the controller 202; and an SCLK↓ signal asa transfer clock of serial data. Among them, the serial data signalsSDATA_C2D and SDATA_D2C are connected to serial communication terminalsof the microcomputer Q301 and communicated with a main chip Q701 of thecontroller, which will be explained hereinlater, by signal switchingcircuits Q304, Q305, Q306, and Q308 for switching the connectingdestination depending on the status of the SLEEP signal, when the SLEEPsignal is at the low level in a mode other than the sleep mode.

[0061] As contents of the communication in a mode other than the sleepmode, various information such as command, status, and the like can betransmitted and received. No transfer clock is connected to themicrocomputer Q301 but asynchronous communication which does not needany transfer clock is made with the controller 202.

[0062] Subsequently, in the sleep mode, the SLEEP signal in FIG. 2 is atthe high level and the serial data signals SDATA_D2C and SDATA_C2D andthe SCLK↓ signal are connected to the S/P conversion unit Q303 and theP/S conversion unit Q302 by the signal switching circuits Q304, Q305,Q306, and Q308. It will be obviously understood from a viewpoint of theconstruction that, as communication contents in the sleep mode, a morevariety of information than that in the mode other than the sleep modecannot be transmitted and received. As mentioned above, the notificationdestination of the information such as status or the like can be changedin accordance with the sleep mode (power saving mode) or the mode otherthan the sleep mode.

[0063] A LOAD signal is connected to the S/P conversion unit Q303. Inthe loading mode, the S/P conversion unit Q303 loads data of an internalserial register into a buffer in the S/P conversion unit Q303 directlyconnected to an output terminal Q0-Q15. In the mode other than theloading mode, the S/P conversion unit Q303 holds the data in the buffer.

[0064] The data in the serial register in the S/P conversion unit Q303is outputted from an SO terminal of the S/P conversion unit Q303synchronously with the SCLK↓ signal in an LSB-first manner. Data at anSI terminal of the S/P conversion unit Q303 is stored into the MSB of ashift register of the S/P conversion unit Q303 synchronously with aclock. The SDATA_D2C signal which is transmitted to the controller isconnected to the SO terminal of the S/P conversion unit Q303 in thesleep mode. The SI terminal of the S/P conversion unit Q303 iscascade-connected to the paper feed option 214 in the sleep mode.

[0065] On the contrary, the LOAD signal is connected to the P/Sconversion unit Q302. In the loading mode, the P/S conversion unit Q302loads data at an input terminal D0-D15 into a serial register in the P/Sconversion unit Q302. The data in the serial register in the P/Sconversion unit Q302 is outputted from an SO terminal of the P/Sconversion unit Q302 synchronously with the SCLK↓ signal in an LSB-firstmanner. Data at an SI terminal of the P/S conversion unit Q302 is storedinto the MSB of a shift register of the P/S conversion unit Q302synchronously with a clock. The SDATA_C2D signal which is received fromthe controller is connected to the SI terminal of the P/S conversionunit Q302 in the sleep mode. The SO terminal of the P/S conversion unitQ302 is cascade-connected to the paper feed option 214 in the sleepmode.

[0066] As mentioned above, according to the construction of FIGS. 3A and3B, in accordance with an instruction of the high level of the SLEEPsignal from the main chip Q701 in FIG. 7, an electric power which issupplied to the microcomputer Q301 is saved. Since the signal switchingcircuits Q304, Q305, Q306, and Q308 are driven in place of themicrocomputer Q301, a situation such that the communication ofinformation such as a status or the like with the controller 202 iscontinuously made while saving an electric power is realized.

[0067]FIG. 4 is a diagram for explaining an interface between thecontroller 202 and the DCON 201 shown in FIG. 2.

[0068] In FIG. 4, C_P_READY is a signal for allowing the DCON 201 toconfirm that the controller 202 is ready for communication. P_P_READY isa signal for allowing the controller 202 to confirm that the DCON isready for communication.

[0069] SCLK↓ is a clock signal for serial communication. SDATA_C2D is adata signal from the controller for serial communication to the DCON201. SDATA_D2C is a data signal from the DCON 201 for serialcommunication to the controller 202.

[0070] PSTART is a signal for allowing the controller 202 to notify theDCON 201 of the print start. VREQ is a signal for allowing the DCON 201to request the controller to start outputting the video data of thesub-scan in response to the PSTART signal. VSYNC is a signal forallowing the controller 202 to notify the DCON 201 of the start of theoutput of valid main scan lines after a predetermined number of mainscan lines and is the signal subsequent to VREQ.

[0071] HREQ is a signal for allowing the DCON 201 to request thecontroller 202 to start outputting the video data of the main scan everymain scan. HSYNC is a signal for allowing the controller to notify theDCON of the output of the valid video data after a predetermined numberof transfer clocks VIDEO_CLK and is the signal subsequent to HREQ.VIDEO_CLK is the transfer clock of VIDEO_DATA.

[0072] VIDEO_DATA is a video data signal of 8 bits. SLEEP is the signalwhich is set to the high level in the sleep mode and outputted from thecontroller 202 to the DCON 201. LOAD is the signal for loading the dataobtained by the serial/parallel conversion and the data obtained by theparallel/serial conversion and is the signal for controlling a currentsupply to a part of the sensors. P5VC is the power source of 5V which issupplied from the controller 202 to the DCON 201 and can be on/offcontrolled.

[0073]FIG. 5 is a diagram for explaining an interface between the DCON201 and the sensor A group 208 shown in FIG. 2. The sensor A group 208is a group of the sensors comprising mechanical microswitches shown inFIGS. 3A and 3B. The same and similar component elements as those inFIGS. 3A and 3B are designated by the same reference numerals.

[0074] In FIG. 5, SW501 is a door open/closure detecting switch fordetecting the open/closure of a door which needs to be opened when theuser accesses a processing system such as fixing unit, drum cartridge,or the like. SW502 is a cassette open/closure detecting upper switch fordetecting the open/closure of an upper cassette.

[0075] SW503 is a cassette open/closure detecting lower switch fordetecting the open/closure of a lower cassette. SW504 is a paperdelivery option connection detecting switch for detecting the connectionof a paper delivery option. SW505 is a paper feed option connectiondetecting switch for detecting the connection of a paper feed option. InFIG. 5, P5VC denotes the power source.

[0076] Q501 and Q502 denote PNP transistors each for controlling on/offof the power source which is supplied to each of the switches SW501 toSW505.

[0077] R501, R502, R503, R504, and R505 denote resistors each forlimiting a value of a current which is supplied to each of the switchesSW501 to SW505.

[0078] R-IN0 denotes a signal for detecting the on/off of the SW501.R-IN1 denotes a signal for detecting the on/off of the SW502. R-IN2denotes a signal for detecting the on/off of the SW503. R-IN3 denotes asignal for detecting the on/off of the SW504. R-IN4 denotes a signal fordetecting the on/off of the SW505. The SLEEP signal and the LOAD signalare the signals each for controlling the power supply of P5VC.

[0079] According to such a construction, in the I/F circuit 301, whenthe PNP transistors Q501 and Q502 are ON, the on/off of the switchesSW501 to SW505 can be detected.

[0080] If the on/off detection of the switches SW501 to SW505 isunnecessary, the transistors Q501 and Q502 are controlled to the offstate and no current is supplied to the switches SW501 to SW505, so thatconsumption of energy can be suppressed.

[0081]FIG. 6 is a diagram for explaining an interface between the DCON201 and the sensor B group 209 shown in FIG. 2. The sensor B group is agroup of the sensors comprising photointerrupters shown in FIGS. 3A and3B.

[0082] In FIG. 6, Q607 denotes a cartridge detecting sensor fordetecting the presence or absence of a cartridge. Q608, Q609, Q610, andQ611 denote an upper paper size 0 sensor, an upper paper size 1 sensor,an upper paper size 2 sensor, and an upper paper presence/absence sensorfor detecting a size of paper enclosed in an upper cassette,respectively.

[0083] Q612, Q613, Q614, and Q615 denote a lower paper size 0 sensor, alower paper size 1 sensor, a lower paper size 2 sensor, and a lowerpaper presence/absence sensor for detecting a size of paper enclosed ina lower cassette, respectively.

[0084] The I/F circuit 3 is the interface circuit with the sensor Bgroup shown in FIGS. 3A and 3B. P5VC is the power source shown in FIGS.3A and 3B. The SLEEP signal and a signal from R-OUT0 are input signalsof the I/F circuit 3 shown in FIGS. 3A and 3B. The power supply to thephotointerrupter sensors is controlled by those signals. R-IN5 to R-IN13denote output signals from the I/F circuit 3 according to outputs of thesensors. Since the power source is efficiently supplied to the sensor Bgroup as necessary as mentioned above, the sensor information can beefficiently obtained and the electric power saving can be realized.

[0085] Q602, Q604, and Q606 denote PNP transistors which are on/offcontrolled by the SLEEP signal and control the power supply to thephotointerrupter sensors, respectively. Q601, Q603, and Q605 denote PNPtransistors which are on/off controlled by R-OUT0, R-OUT1, and R-OUT2and control the power supply to the photointerrupter sensors,respectively. R601 to R609 denote current limiting resistors forcontrolling the currents to the photointerrupters, respectively.

[0086] In such a construction, since the sensor B group has aconstruction such that the power supply is selected in accordance withthe transmission data, the current supply to the photointerruptersensors can be turned off in the cases other than the necessary case.Thus, the electric power consumption in the sleep mode can be reduced.

[0087]FIG. 7 is a diagram for explaining a detailed construction of thecontroller 202 shown in FIG. 2.

[0088] In FIG. 7, reference numerals 701 to 708 denote interfacecircuits (I/F circuits) each for realizing an interface between aspecific device and a 1-chip microcomputer Q702 or the main chip Q701.

[0089] In FIG. 7, each of P5VA, P5VB, and P5VC denotes the power sourceof 5V. Each of P5VA and P5VB indicates the power source which issupplied from the DC power source 203. P5VA is always supplied to drivethe sub-CPU or the like. P5VB is supplied only during the image formingoperation such as a copying/printing operation or the like or in thestandby mode. P5VC is the power source which is realized on the basis ofthe power source of P5VA and is the power source which is on/offcontrolled by Q705 in the controller so as to intermittently supply thepower source to the DCON and the RCON, respectively. By saving the powersource other than P5VA in the power saving mode (sleep mode),unnecessary electric power consumption can be reduced. Particularly,since P5VB stops the power supply circuit in the power source, a largeeffect of reducing the electric power consumption can be obtained.

[0090] P5VA, P5VB, and P5VC are applied not only to FIG. 7 but also toFIGS. 3A, 3B, 4, 5, 6, 8A, 8B, 9, and 10 in common. The power sourcesP5VA, P5VB, and P5VC in those diagrams are controlled in accordance withflowcharts of FIGS. 11, 12, 13, and 14, respectively.

[0091] The main chip Q701 includes: a microprocessor for executingcontrol programs stored in a ROM Q703 by using a RAM Q704 which isbacked up by a battery BT 701 even if the power source is OFF and holdsthe data as a work area; an interruption control circuit for controllingvarious interruption signals; a DMA control circuit; various timers; animage processing circuit; a resolution converting circuit; input/outputport interface circuits; and the like. The main chip Q701 controls thewhole controller.

[0092] Further, the main chip Q701 is connected to X′tal X701 andincludes a PLL circuit for generating internal operation clocks. The PLLcircuit has a function for stopping the generation of the clocks whenthe microprocessor enters the sleep mode for saving the electric powerand suppressing the electric power consumption of the whole chip.

[0093] The 1-chip microcomputer (sub-chip) Q702 has a circuit similar tothat of a general microcomputer comprising a CPU, a RAM, a ROM, and thelike. A microcomputer of small electric power consumption is used assuch a microcomputer because a logic which is complicated more than themain chip is not used, a clock frequency of the CPU is low, it has amemory of a small capacity, and the like. Partial ordinary operations ofthe main chip such as status update, driving of the LAN-UNIT 207 fornotifying the outside of the information, and the like can be executedby the 1-chip microcomputer even in the sleep mode. The power control inthe sleep mode, status monitoring, monitoring of commands from thenetwork, response, and the like can be also executed although they willbe explained in detail hereinlater.

[0094] An interruption signal 709 from the 1-chip microcomputer(sub-chip) Q702 is inputted to an NMI (non-maskable interruption)terminal of the main controller (main chip) Q701. When the interruptionsignal is inputted to the NMI terminal if the microprocessor is in thesleep mode, the sleep mode is cancelled, the PLL circuit is enabled, theclock is supplied to the whole main chip, and the main chip restarts theoperation.

[0095] The 1-chip microcomputer Q702 monitors the sensor signals of theRCON 216 and the DCON 201 in the sleep mode and monitors a sleeprecovery signal of the FAX-UNIT 206. Further, in the sleep mode, themicrocomputer Q702 sends a command response and the status informationto the LAN-UNIT 207 in place of the main chip Q701.

[0096] The 1-chip microcomputer Q702 and the main chip Q701 can transmitand receive commands and data by serial communication 710. Theinterruption signal 709 from the 1-chip microcomputer Q702 mentionedabove is inputted to the NMI terminal of the main chip. An ACTIVE signal711 indicating whether the main chip Q701 is in the sleep mode or theoperative mode is also inputted.

[0097] The power switch 223 is provided on the operation unit 222. Thedigital hybrid apparatus of the embodiment is shifted to the sleep modeor recovered from the sleep mode by an input of the power switch 223.

[0098] The timing to shift to the sleep mode is not limited to thetiming of the input of the power switch 223 but the apparatus can bealso automatically shifted to the sleep mode when the digital hybridapparatus is held in the standby mode for a predetermined time which canbe selected by the setting from the operation unit 222.

[0099] The timing for recovery from the sleep mode is not limited to thetiming of the input of the power switch 223 but the apparatus can bealso recovered by a command from the LAN, a call signal from thetelephone line, or the like as will be explained hereinlater.

[0100] A SLEEP signal 712 indicative of the shift to the sleep mode isset to the high “H” level in the sleep mode. The signal is sent from themain chip Q701 to the RCON 216 via an I/F circuit 706 with the RCON andto the DCON 201 via an I/F circuit 701 with the DCON.

[0101] In the sleep mode, the power sources other than P5VA as a DCpower source is turned off by a control signal from the 1-chipmicrocomputer Q702 and, further, the power source of P5VC is alsointermittently turned on/off by the transistor Q705, thereby reducingthe electric power consumption.

[0102] The RCON 216 A/D converts the image signal obtained from thephotoelectric converting device such as a CCD or the like, executes areading image process such as a shading process or the like to theobtained digital signal, and outputs a video signal of 8 bits.

[0103] Signals indicative of statuses of various sensors such as anoriginal size and the like are also outputted to the controller and,further, a motor of the reader unit is controlled. The I/F-9 has signallines of a vertical sync signal (output), a horizontal sync signal(output), a vertical sync request signal (input), a horizontal syncrequest signal (input), the clock (output), the video signal of 8 bits(input), a video signal ready signal (input), the SLEEP signal 712(output), the LOAD signal (output), and the like. Further, the sensorinformation of the RCON is inputted by the serial communication.

[0104] The I/F circuit 706 with the RCON 216 sends each of the signalsof the I/F-9 to the main chip Q701. However, since the main chip Q701cannot receive the signals in the sleep mode, they are sent to the1-chip microcomputer Q702. Such a switching operation is executed by theSLEEP signal 712 from the main chip Q701.

[0105] The DCON 201 records the images as described in FIGS. 3A and 3B.The I/F-1 has the signal lines described in FIG. 4. The sensor signal ofthe DCON 201 is inputted together with the command status signal by theserial communication.

[0106] The I/F circuit 701 with the DCON 201 sends the signals of theI/F-1 to the main chip Q701. However, since the main chip Q701 cannotreceive the signals in the sleep mode, they are sent to the 1-chipmicrocomputer Q702. Such a switching operation is executed by the SLEEPsignal 712 from the main chip Q701.

[0107] In the I/F-1, it is also possible to construct in a manner suchthat eight VIDEO_DATA signals are used to transfer the image signal inthe normal mode and they are switched to the seven sensor signals andthe LOAD signal by the SLEEP signal in the sleep mode and the switchedsignals are used, thereby reducing the number of signal lines of theI/F-1.

[0108] When the image is read out, the video signal which is inputtedfrom the RCON 216 via the I/F-9 is transferred to the image processingunit, subjected to an image process, and stored into the RAM Q704.

[0109] When the image is recorded, the image data in the RAM Q704 isread out, image processes and resolution conversion are executed on thebasis of a size of recording paper and various settings, and the imagedata is outputted to the DCON 201 via the I/F-1.

[0110] The LAN-UNIT 207 includes: a physical layer (PHY) for connectingto the Ethernet (registered trademark); an Ethernet (registeredtrademark) connecting circuit for controlling an MAC layer; a LANcontrol unit for making communication control of IEEE802.3; and thelike.

[0111] A LAN-UNIT I/F circuit 702 is an interface circuit of USB orIEEE1284, sends the information received via the I/F-10 from theLAN-UNIT 207 to the main chip Q701 and sends the information from themain chip to the LAN-UNIT 207.

[0112] For example, if the command to request the status of the digitalhybrid apparatus of the embodiment is detected via the LAN-UNIT 207, thestatus request command is sent from the LAN-UNIT I/F circuit to the mainchip Q701. The main chip Q701 transfers the necessary status held in astoring unit (RAM) from the main chip Q701 to the LAN-UNIT I/F circuit.The LAN-UNIT I/F circuit sends this information to the LAN-UNIT via theI/F-10.

[0113] If a print job is issued from the PC on the network, a command torequest the print is sent from the LAN-UNIT I/F circuit to the main chipQ701. When the apparatus enters a print ready mode, a responseindicative of the print ready state is sent from the main chip Q701 tothe LAN-UNIT I/F circuit. The LAN-UNIT I/F circuit sends thisinformation to the LAN-UNIT via the I/F-10.

[0114] When the PC (information processing apparatus) on the networkreceives this response, it subsequently transmits the print data.Therefore, the print data is inputted to the main chip Q701 by a similarsignal flow and subjected to necessary image processes by the main chipQ701 and, thereafter, the processed print data is temporarily storedinto the RAM. In a manner similar to the processes upon image recording,the image data is sent as an image signal of the I/F-1 to the DCON andrecorded.

[0115] The above operations relate to the case where the main chip Q701is normally operating and the operations in the sleep mode are slightlydifferent from them.

[0116] In the sleep mode, the transmission and reception of the commandsto/from the network are executed by the 1-chip microcomputer Q702. TheLAN-UNIT I/F circuit 702 transfers the information received via theI/F-10 from the LAN-UNIT 207 to the 1-chip microcomputer Q702 and sendsthe information from the 1-chip microcomputer Q702 to the LAN-UNIT 207.

[0117] In the sleep mode, since the main chip Q701 is in the sleep modeand is in a state where the signals cannot be transmitted and received,the 1-chip microcomputer Q702 receives the status information from theI/F circuit 706 with the RCON 216 and the I/F circuit 701 with the DCON201 and monitors them. As will be described in other diagrams(flowcharts), when the status request command is received from theLAN-UNIT 207, the 1-chip microcomputer Q702 sends the status informationas a response to the LAN-UNIT.

[0118] If the sleep mode of the digital hybrid apparatus is cancelled bya reason such that the print job to the digital hybrid apparatus in theembodiment is generated in the sleep mode or the like, first, the 1-chipmicrocomputer Q702 discriminates whether the command received from theLAN-UNIT have the contents which cannot be processed if the apparatus isnot recovered from the sleep mode or not. If the command such as a printrequest which cannot be processed if the apparatus is not recovered fromthe sleep mode is received, the 1-chip microcomputer Q702 instructs apower control I/F circuit 705 to turn on the power source in the offstate in the sleep mode. The power control I/F circuit sends a power-onsignal to the DC power source 203.

[0119] The 1-chip microcomputer Q702 outputs the interruption signal(NMI) 709 to the NMI terminal of the main chip Q701. The main chip Q701which received the interruption signal 709 from the NMI terminal isshifted from the sleep mode to the normal mode as will be explained withreference to another diagram (flowchart). When the 1-chip microcomputerQ702 confirms by the ACTIVE signal 711 that the main chip Q701 hasentered the normal mode, the 1-chip microcomputer Q702 notifies the mainchip Q701 of the contents of the received command by the serialcommunication 710. If the main chip Q701 determined that the digitalhybrid apparatus has been set to the mode in which the received commandcan be processed (for the print command, when it is confirmed that theapparatus has been activated to the recording ready mode), the main chipQ701 sends the necessary response to the LAN-UNIT.

[0120] The FAX-UNIT 206 includes: a CODEC for encoding and decoding theimage data; a MODEM for modulating the encoded data in order to performthe FAX transmission and demodulating the received FAX signal; a FAXcontrol unit for executing a FAX protocol; a CI detecting circuit fordetecting a call signal (CI) and outputting a CI detection signal; anoff-hook detecting circuit for detecting an off-hook and outputting anoff-hook detection signal; and the like.

[0121] An I/F circuit 703 with the FAX-UNIT is an IEEE1284 interfacecircuit and transmits and receives commands and the image data to/fromthe FAX-UNIT 206 via the I/F-11. The I/F circuit 703 also receives theCI detection signal (input) and the off-hook detection signal (input).

[0122] Upon FAX transmission, the image data stored in the RAM Q704 issent to the FAX-UNIT and FAX-transmitted. Upon FAX reception, the imagedata is received from the FAX-UNIT and temporarily stored into the RAM.In a manner similar to the processes upon image recording, the imagedata is sent as an image signal of the I/F-1 to the DCON and recorded.

[0123] In the sleep mode, the CI detection signal and the off-hookdetection signal in the I/F-11 are monitored. When the CI incoming callor the off-hook is detected, an ACTIVATION signal 713 from the FAX issent to the 1-chip microcomputer Q702 and the main chip Q701. The 1-chipmicrocomputer which received the ACTIVATION signal from the FAXactivates the power source, recovers the main controller from the sleepmode, and sets the apparatus into a state where it can respond to thecommand from the FAX-UNIT.

[0124] Although the ACTIVATION signal 713 from the FAX has been inputtedto both of the 1-chip microcomputer Q702 and the main chip Q701 in theabove description, it is also possible to construct in a manner suchthat the FAX-ACTIVATION signal 713 is inputted only to the 1-chipmicrocomputer Q702 and it is notified that the 1-chip microcomputer Q702has been activated by the ACTIVATION signal from the FAX-UNIT by theserial communication 710.

[0125]FIGS. 8A and 8B are diagrams for explaining a construction of theRCON 216 shown in FIG. 2 and the same and similar component elements asthose in FIG. 2 are designated by the same reference numerals.

[0126] In FIGS. 8A and 8B, the RCON 216 has a construction such that theprinter DC load group 211 is replaced with the reader DC load group 220in FIG. 2 as compared with the DCON shown in FIGS. 3A and 3B. Referencenumerals 901 to 904, 908, and 909 denote interface circuits (I/Fcircuits). The I/F circuit 901 has an I/F circuit 2 and an I/F circuit 3of the RCON 216. The I/F circuit 902 has an I/F circuit DC3 of the RCON216.

[0127] The I/F circuit 903 has an I/F circuit 4 with the RCON 216. TheI/F circuit 904 has an I/F circuit 5 of the RCON 216. The I/F circuit908 is an I/F circuit 6 of the RCON 216. The I/F circuit 909 is an I/Fcircuit 1 of the RCON 216.

[0128] The AC driver 205, I/F circuit 305, paper delivery option 213,I/F circuit 306, paper feed option 214, I/F circuit 307, units 212regarding the laser, and I/F circuit 308 in FIGS. 3A and 3B do not existin the RCON 216. The signal lines connected to those component elementsdo not exist. The image sensor 221 is a sensor for reading the image.

[0129] PW-DC-3 is the power I/F of the RCON 216. Q901 denotes amicrocomputer of the RCON 216. Q902 denotes a parallel/serial (P/S)converter of the RCON 216. Q903 denotes a serial/parallel (S/P)converter of the RCON. Q904 denotes a tristate buffer of the RCON 216.Q906 denotes a tristate buffer of the RCON 216.

[0130]FIG. 9 is a diagram for explaining details of the I/F circuit 18of the paper feed option 214 shown in FIGS. 3A and 3B. Fundamentalconstruction and operation are substantially the same as those of theRCON 216 and the I/F circuit 2 of the DCON 201.

[0131] In FIG. 9, SW1002 denotes a cassette open/closure detecting upperswitch for detecting the open/closure of an upper cassette. SW1003denotes a cassette open/closure detecting lower switch for detecting theopen/closure of a lower cassette. P5VC is the power source shown inFIGS. 3A and 3B.

[0132] Q1001 and Q1002 denote PNP transistors for controlling the on/offof power sources which are supplied to the switches SW1002 and SW1003.R1002 and R1003 denote resistors for limiting values of currents whichare supplied to the switches SW1002 and SW1003.

[0133] R-IN 17 denotes a signal for detecting the on/off of the switchSW1002. R-IN 18 denotes a signal for detecting the on/off of the switchSW1003. The SLEEP signal and the LOAD signal are the signals forcontrolling the power supply of P5VC.

[0134] In such a construction, in the I/F circuit 18, the on/off of theswitches SW1002 and SW1003 can be detected when the transistors Q1001and Q1002 are ON.

[0135] If the on/off detection of the switches SW1002 and SW1003 isunnecessary, the transistors Q1001 and Q1002 are turned off and thecurrents are not supplied to the switches SW1002 and SW1003, therebyenabling the energy consumption to be suppressed.

[0136]FIG. 10 is a diagram for explaining an interface between the I/Fcircuit 3 of the paper feed option 214 and the sensor B group 209 shownin FIGS. 3A and 3B. Fundamentally, this interface has a constructionsimilar to that of each of the RCON and the DCON and executes a similaroperation. The sensor B group is a group of the sensors comprising thephotointerrupters.

[0137] In FIG. 10, Q1108 denotes an upper paper size 0 sensor fordetecting a size of paper enclosed in the upper cassette. Q1109 denotesan upper paper size 1 sensor for detecting the size of paper enclosed inthe upper cassette. Q1110 denotes an upper paper size 2 sensor fordetecting the size of paper enclosed in the upper cassette. Q1111denotes an upper paper presence/absence sensor for detecting thepresence or absence of the paper in the upper cassette.

[0138] Q1112 denotes a lower paper size 0 sensor for detecting a size ofpaper enclosed in the lower cassette. Q1113 denotes a lower paper size 1sensor for detecting the size of paper enclosed in the lower cassette.Q1114 denotes a lower paper size 2 sensor for detecting the size ofpaper enclosed in the lower cassette. Q1115 denotes a lower paperpresence/absence sensor for detecting the presence or absence of thepaper in the lower cassette.

[0139] P5VC is the power source shown in FIGS. 3A and 3B. The SLEEPsignal, R-OUT 17, and R-OUT 18 indicate the input signals of the I/Fcircuit 3. The power supply to the photointerrupter sensors iscontrolled by those signals.

[0140] R-IN 22 to R-IN 29 denote output signals from the I/F circuit 3.

[0141] Q1104 and Q1106 denote PNP transistors which are on/offcontrolled by the SLEEP signal and control the power supply to thephotointerrupter sensors.

[0142] Q1103 and Q1105 denote PNP transistors which are on/offcontrolled by R-OUT 17 and R-OUT 18 and control the power supply to thephotointerrupter sensors, respectively. R1102 to R1109 denote currentlimiting resistors for controlling the currents to thephotointerrupters, respectively.

[0143] By the construction as mentioned above, the current supply to thephotointerrupter sensors can be turned off in the cases other than thenecessary case.

[0144] In the above construction, the shift to the power saving sleepmode, the recovery to the normal mode, and the status monitoring of theDCON and the RCON, the command monitoring from the LAN-UNIT, and thestatus transmission to the LAN-UNIT in the sleep mode are controlled bythe 1-chip microcomputer Q702 (hereinafter, referred to as a sub-CPU)and the main chip Q701 (hereinafter, referred to as a main CPU). Thoseoperations will be described hereinbelow with reference to flowcharts ofFIGS. 11, 12, 13, and 14.

[0145]FIG. 11 is the flowchart showing an example of a first controlprocedure in the image forming apparatus according to the invention andcorresponds to an operating procedure of the sub-CPU. S201 to S217denote processing steps.

[0146] The sub-CPU is connected to the DC power source P5VA and isalways operating. The operation is mainly classified into the operationin the sleep mode in which the main CPU is in a halt mode and theoperation in the normal mode in which the main CPU is executing thenormal operation. First, the normal mode will be described.

[0147] Whether the ACTIVE signal 711 from the main CPU is ON or not isdiscriminated. If it is ON (S201), the apparatus is in the normal modeand the statuses of the DCON 201 and the RCON 216 are received from themain CPU (S202). The operation to monitor the power switch 223 isrepeated (S203).

[0148] If it is determined that the power switch 223 has been pressed, asystem-down request (SYSTEM DOWN) is transmitted to the main CPU so asto shift the whole system to the power saving sleep mode (S204). Thereception of the statuses and the request for the system-down areexecuted by using the serial communication 710 between the sub-CPU andthe main CPU.

[0149] When the ACTIVE signal from the main CPU is turned off (S201),the apparatus is shifted to the power saving sleep mode. Factors bywhich the ACTIVE signal is turned off will be explained hereinlater.When the apparatus is shifted to the power saving sleep mode, first, thepower control I/F circuit 705 is instructed to turn off the power sourceP5VB to the system of the DCON 201 and the RCON 216 (S205).

[0150] Subsequently, a timer to monitor the statuses of the DCON 201 andthe RCON 216 is started (S206). This timer counts a time interval forobtaining the statuses. In the embodiment, a time interval of 100 msecis counted.

[0151] The operation to monitor whether there is a FAX job request ornot (S207), whether there is a print job request or not (S208), whetherthe power switch has been pressed or not (S209), and whether there is astatus request from the external apparatus or not (S210) is repeateduntil the time interval of 100 msec is counted. If there is the jobrequest (YES in S207, S208) and if the power switch has been pressed(YES in S209), the power control I/F circuit 705 is instructed to turnon the power source P5VB to the system of the DCON 201 and the RCON 216(S211). The main CPU ACTIVATION signal 709 is turned on (S212). Afterthat, the apparatus waits for the activation of the main CPU (ACTIVATIONsignal is ON) (S213). The information such as factors of the activationin step S209, commands received from the LAN-UNIT in steps S207 andS208, and the like is transferred to the main CPU (S214). The processingroutine is returned to step S201 and the apparatus is shifted to thenormal mode.

[0152] The presence or absence of the FAX job in step S207 isdiscriminated by the CI detection signal and the off-hook detectionsignal which are supplied from the FAX-UNIT I/F circuit 703 mentionedabove. The presence or absence of the print job is discriminated by thecommand which is supplied from the LAN-UNIT I/F circuit 702 mentionedabove and this command is transferred to the main CPU.

[0153] If the status request is made by the external apparatus (S210),the held latest statuses are transmitted to the external apparatus viathe LAN-UNIT (S215). The status information transmitted (notified) tothe external apparatus is displayed as status information onto a displayunit provided for the external apparatus. The user can confirm thelatest statuses.

[0154] The statuses of the DCON 201 and the RCON 216 which aretransmitted here are the latest statuses of either the statuses receivedfrom the main CPU or the statuses obtained in step S217.

[0155] When the status monitoring timer counts 100 msec (naturally, thetime interval is not limited to 100 msec) (S216), the statuses areobtained from the DCON 201 and the RCON 216 (S217) and the processes instep S206 and subsequent steps are repeated. Details of the statusobtaining operation in step S217 will be explained hereinlater withreference to FIG. 13. Although the above explanation has been made onthe assumption that the status monitoring timer has been set to 100msec, for example, if the status monitoring timer is set to a longertime such as 10 seconds or 30 seconds, the frequency of the power supplyon the image forming apparatus side decreases. Thus, the further largepower saving effect can be obtained and an effect such that the properupdated latest status can be provided for the user can be obtained.

[0156] As mentioned above, according to the flowchart of FIG. 11, thepower source of P5VB is saved so long as the processes regarding theimage creation or the depression of the power switch is not detected.Despite that the main CPU is in the power saving mode, the sub-CPU ofthe small electric power consumption can make a response of the statusesto the status request from the outside (S210). Although the statuseswhich are responded to the outside are updated in accordance with theprocess in step S217, the power saving is also made in the statusprocess in step S217.

[0157] Subsequently, the operation of the main CPU will be describedwith reference to the flowchart of FIG. 12.

[0158]FIG. 12 is the flowchart showing an example of a second controlprocedure in the image forming apparatus according to the invention andcorresponds to an operating procedure of the main CPU. S301 to S322denote processing steps.

[0159] The main CPU is connected to the DC power source P5VA and isalways operating in a manner similar to the sub-CPU. The operation ismainly classified into the operation in the sleep mode in which the mainCPU is in the halt mode in which the CPU clock (X701) is stopped and theoperation in the normal mode in which all of the operations of thesystem such as transmission and reception of the FAX, printingoperation, scanning operation, status request response from the externalapparatus, and the like can be executed.

[0160] When the main CPU is shifted to the normal mode (from the haltmode), first, the ACTIVE signal 711 is turned on (S301). As mentionedabove, the sub-CPU enters the normal mode by this operation.Subsequently, the factors of the activation and the command are receivedfrom the sub-CPU (S302). At this time, the command which is received isthe command received by the sub-CPU from the LAN-UNIT. The command isprocessed in step S307 and subsequent steps.

[0161] Subsequently, the SLEEP signal 712 is turned off (S303). Asmentioned above, by this operation, in the controller, the serialcommunication I/F between the DCON-I/F circuit 701 and the DCON 201 andbetween the RCON-I/F circuit 706 and the RCON 216 is switched from thesub-CPU to the main CPU in the DCON-I/F circuit 701 and the RCON-I/Fcircuit 706.

[0162] Also in the DCON 201 and the RCON 216, the sleep mode of the DCONmicrocomputer Q301 and the RCON microcomputer Q901 is cancelledsimultaneously with that the serial communication I/F is switched fromthe hardware construction to the DCON microcomputer Q301 and the RCONmicrocomputer Q901.

[0163] Subsequently, a timer to shift to the power saving sleep mode isstarted (S304). This timer is a timer for counting a time interval whichis required when the apparatus is again shifted from the normal mode tothe power saving sleep mode. In the embodiment, a time interval of onehour is counted. The operation to monitor whether the statuses from theDCON 201 and the RCON 216 have been received or not (S305), whetherthere is a system-down request from the sub-CPU or not (S306), whetherthere is a FAX job request or not (S307), whether there is a print jobrequest or not (S308), whether there is a job request from the DCONmicrocomputer Q301 or not (S309), whether there is a job request fromthe RCON microcomputer Q901 or not (S310), and whether there is a statusrequest from the external apparatus or not (S311) is repeated until thetime interval of one hour is counted.

[0164] If there is the system-down request (S306), a process forshifting to the power saving sleep mode in step S315 and subsequentsteps, which will be explained hereinlater, is executed.

[0165] If there is the job request, a predetermined job is executed(S312). The time of one hour is again set to the power saving sleep modeshifting timer and the timer is restarted (S313). The processing routineis returned to step S305.

[0166] The presence or absence of the FAX job is discriminated by the CIdetection signal and the off-hook detection signal which are suppliedfrom the FAX-UNIT I/F circuit 703 mentioned above or by the commandreceived from the sub-CPU in step S302. The presence or absence of theprint job is discriminated by the command which is supplied from theLAN-UNIT I/F circuit 702 mentioned above or the command received fromthe sub-CPU in step S302. The job requests from the DCON and the RCONare received by the serial communication I/F of each of them.

[0167] The presence or absence of the status request from the externalapparatus is discriminated by the command which is supplied from theLAN-UNIT I/F circuit 702 mentioned above. Any of the general jobexecuting methods can be used and its detailed explanation is omitted.

[0168] When the timer for shifting to the power saving sleep mode countsone hour, that is, if one hour has elapsed in a state where no job isexecuted (naturally, the time interval is not limited to one hour)(S314), the process for shifting to the power saving sleep mode in stepS315 and subsequent steps is executed in order to shift to the powersaving sleep mode by the main CPU itself.

[0169] Subsequently, the process for shifting to the power saving sleepmode in step S315 and subsequent steps will be explained. As mentionedabove, this process is the power saving sleep mode shifting processwhich is executed in the case where there is the system-down requestfrom the sub-CPU (S306) or in the case where the main CPU is shifted tothe power saving sleep mode by itself by the power saving sleep modeshifting timer (S314). First, a power-off prediction is transmitted tothe DCON and the RCON via the serial communication I/F (S315). Theapparatus waits for reception of a power-off permission response fromeach of the DCON 201 and the RCON 216 (S316).

[0170] When the DCON microcomputer and the RCON microcomputer areconstructed in a manner such that when the power-off prediction isreceived, a predetermined power-off process is executed and, aftercompletion of the power-off process, the power-off permission istransmitted to the main CPU.

[0171] If the power-off permission responses are received from both ofthe DCON microcomputer and the RCON microcomputer (S316), the statusesof the DCON and the RCON are transmitted to the sub-CPU (S317). Thestatuses of the DCON and the RCON which are transmitted here are thelatest statuses received from the DCON microcomputer and the RCONmicrocomputer in step S305.

[0172] Subsequently, the SLEEP signal 712 is turned on (S318). Asmentioned above, by this operation, in the controller, in the DCON-I/Fcircuit 701 and the RCON-I/F circuit 706, the serial communication I/Fwith the DCON and the RCON is switched from the main CPU to the sub-CPU.Also in the DCON and the RCON, the DCON microcomputer and the RCONmicrocomputer are set to the sleep mode simultaneously with that theserial communication I/F is switched from the DCON microcomputer Q301and the RCON microcomputer Q901 to the hardware construction.

[0173] Subsequently, the ACTIVE signal 711 is turned off (S319). Asmentioned above, the sub-CPU enters the power saving sleep mode by thisoperation.

[0174] Subsequently, the main CPU itself is set to the halt mode inwhich the CPU clock (X701) has been stopped and the shift to the powersaving sleep mode is completed (S320). This state is continued until theinterruption is caused by the main CPU ACTIVATION signal 709 which issupplied from the sub-CPU. When the interruption is caused (S321), thehalt mode is cancelled (S322) and the processing routine advances tostep S301 in the normal mode.

[0175] Subsequently, the operation by which the sub-CPU obtains thestatus from the DCON in the power saving sleep mode will be describedwith reference to the flowcharts of FIGS. 13 and 14.

[0176]FIGS. 13 and 14 are the flowcharts showing an example of a thirdcontrol procedure in the image forming apparatus according to theinvention and correspond to an operating procedure (detailed procedureof the status obtainment processing procedure in step S217 shown in FIG.11) of the sub-CPU. S401 to S430 indicate processing steps,respectively.

[0177] First, P5VC is turned on in order to enable a hardware serialcommunication block of the DCON and the paper feed unit to operate(S401). By driving P5VC, as shown in FIGS. 5 and 6, the currents aresupplied to the I/F circuits 2 and 3, so that the sensor A group and thesensor B group are set into a state where they can detect the signals.Thus, it corresponds to the case where upon updating of the status, thesupply of the power source (current supply to the sensor groups)necessary for the status updating in which the electric power is savedin the power saving mode is controlled. The status updated according tosuch control is notified to the external apparatus via the LAN-UNIT 207on the basis of the processes of the sub-CPU in step S215 in FIG. 11.

[0178] Subsequently, the LOAD signal is set to the low “L” level (S402).The apparatus waits for 100 μsec until the input data of the P/Sconversion unit Q302 is stabilized (S403). After that, the LOAD signalis set to the high “H” level and the input data of the P/S conversionunit is decided (S404).

[0179] Subsequently, transmission data 0000(hex) is set (S405) so as toturn off the current supply of the sensor B group 209 and 32 clocks clkare generated from the clock signal SCLK↓, thereby transmitting andreceiving the data of 32 bits (S406). Thus, the status of the sensor Agroup can be received. At this time, although the information of thesensor B group is also received in association with it, since the powersupply is OFF, control is made so as to invalidate the data.

[0180] Explanation will be made in detail. The transmission data0000(hex) is transmitted to the S/P conversion unit Q303 via SDATA_C2Dand the data of R-IN31 to R-IN0 is received by the P/S conversion unitQ302 via SDATA_D2C. The data R-IN5 to R-IN16 and R-IN19 to R-IN31received at this time is the invalid data. When the paper feed unit isnot connected, upper 16 bits of the transmission/reception data isinvalid data.

[0181] Subsequently, the LOAD signal is set to the L level (S407). Afterthe apparatus waits for 100 μsec (S408), the LOAD signal is set to the Hlevel and the output data of the S/P conversion unit Q303 is decided(S409). The next transmission data as data in the register for checkinga change in status is cleared to 0 and initialized (S410). Step S410 isa processing step for clearing a communication buffer.

[0182] Subsequently, the received status of the sensor A group iscompared with the obtained latest status.

[0183] When the door open/closure detecting switch (SW501) correspondingto bit 0 (R-IN0) of the reception data is open (S412), bit 0 of the nexttransmission data is set (“is set” written here denotes that the bit isset from 0 to 1), thereby allowing a detection result of the cartridgedetecting sensor (Q607) to be outputted to the R-IN5 upon transmissionof the next data (S413).

[0184] When the cassette open/closure detecting upper switch (SW502)corresponding to bit 1 (R-IN1) of the reception data changes from theopen state to the closing state (S414), bit 1 of the next transmissiondata is set, thereby allowing detection results of the upper cassettesize 0 sensor (Q608), upper cassette size 1 sensor (Q609), uppercassette size 2 sensor (Q610), and upper paper presence/absence sensor(Q611) to be outputted to R-IN6 to R-IN9 upon transmission of the nextdata (S415).

[0185] When the cassette open/closure detecting lower switch (SW503)corresponding to bit 2 (R-IN2) of the reception data changes from theopen state to the closing state (S416), bit 2 of the next transmissiondata is set, thereby allowing detection results of the lower cassettesize 0 sensor (Q612), lower cassette size 1 sensor (Q613), lowercassette size 2 sensor (Q614), and lower paper presence/absence sensor(Q615) to be outputted to R-IN10 to R-IN13 upon transmission of the nextdata (S417).

[0186] If the paper feed option connection detecting switch (SW505)corresponding to bit 4 (R-IN4) of the reception data indicates thepresence of the connection (S418), a change in cassette open/closurestate of the option cassette in step S419 and subsequent steps isdiscriminated. If the absence of the connection is detected, processesin step S423 and subsequent steps are executed.

[0187] If the option cassette open/closure detecting upper sensorcorresponding to bit 17 (R-IN17) of the reception data changes from theopen state to the closing state (S419), bit 17 of the next transmissiondata is set, thereby allowing detection results of the option uppercassette size 0 sensor, option upper cassette size 1 sensor, optionupper cassette size 2 sensor, and option upper paper presence/absencedetecting sensor to be outputted to R-IN22 to R-IN25 upon transmissionof the next data (S420).

[0188] If the option cassette open/closure detecting lower sensorcorresponding to bit 18 (R-IN18) of the reception data changes from theopen state to the closing state (S421), bit 18 of the next transmissiondata is set, thereby allowing detection results of the option lowercassette size 0 sensor, option lower cassette size 1 sensor, optionlower cassette size 2 sensor, and option lower paper presence/absencedetecting sensor to be outputted to R-IN26 to R-IN29 upon transmissionof the next data (S422).

[0189] The case where the next transmission data is equal to 0 (S423)corresponds to the case where it is unnecessary to detect the statusesof the sensor B group. Only the data of the sensor A group in whichthere is a change is updated, P5VC is turned off (S424), and theobtaining and discriminating processes of the statuses are finished. Bythe process in step S424, after completion of the status update, controlfor saving the power source necessary for updating the statuses isrealized, and the electric power consumption can be further reduced.

[0190] The case where the next transmission data is equal to a valueother than 0 (S423) corresponds to the case where it is necessary todetect the statuses of the sensor B group. Secondary obtaining anddiscriminating processes of the statuses in step S425 and subsequentsteps are executed. As mentioned above, by the discriminating process instep S423, if the opening of the door is detected or if there is achange in open/closure of the cassette in step S412, the data of thesensor B group is collected in an interlocking relational manner.Therefore, the status data can be efficiently collected. On thecontrary, when a possibility that the data of the sensor B group isunnecessary is high, the further large electric power saving can berealized without performing the status collection based on the sensor Bgroup.

[0191] First, the data of 32 bits of the next transmission datamentioned above is transmitted (S425) by generating 32 clocks clk fromthe clock signal SCLK↓ (at this time, since the received data is theinvalid data, it is abandoned). Subsequently, the LOAD signal is set tothe L level (S426). After the apparatus waits for 100 μsec (S427), theLOAD signal is set to the H level (S428). By this operation, the outputdata of the S/P conversion unit is decided and the statuses of thesensor B group are decided as input data of the P/S conversion unit. Byreceiving the data of 32 bits (S429) by again generating 32 clocks clkfrom the clock signal SCLK↓, the statuses of the sensor B group areobtained.

[0192] At this time, the transmitted data is the invalid data becausethe on/off control of the LOAD signal is not made.

[0193] Subsequently, only the valid data in the received data is updated(S430), processes in step S424 and subsequent steps are executed, andthe obtaining and discriminating processes of the statuses are finished.

[0194] The valid data denotes bit 5 of the reception data if bit 0 ofthe data transmitted in step S429 is equal to 1. It denotes bit 6 to bit9 of the reception data if bit 1 of the transmitted data is equal to 1.It denotes bit 10 to bit 13 if bit 2 of the transmitted data is equalto 1. It denotes bit 22 to bit 25 of the reception data if bit 17 of thetransmitted data is equal to 1. It is bit 26 to bit 29 of the receptiondata if bit 18 of the transmitted data is equal to 1. In the othercases, all of the data is the invalid data.

[0195] Although the obtaining and discriminating operations of thestatuses from the DCON and the paper feed unit have been described inthe above flowcharts, the apparatus also has a function for obtainingand discriminating the statuses of the sensor D group (217) and thesensor E group (218) by a similar method for the RCON. When theobtaining and discriminating operations of the statuses are executedfrom the DCON and the paper feed unit, the status obtaining anddiscriminating operations from the RCON are also simultaneouslyexecuted.

[0196] As mentioned above, according to the flowcharts of FIGS. 13 and14, the current can be always supplied to P5VA which is necessary fordetection or the like of a predetermined signal from the outsideincluding the sub-CPU and the apparatus can be shifted to a state whereP5VB necessary for executing the image creation (the units 212 regardingthe laser, and the like) and the paper feed driving (the paper feedoption 214, etc.) has been saved.

[0197] [Second Embodiment]

[0198] The first embodiment has been described on the assumption thatthe sub-CPU (1-chip microcomputer Q702) and the main chip Q701 arephysically separately provided as shown in FIG. 7. However, theinvention is not limited to it but there is also presumed a case where amode for making a predetermined chip (CPU) operative by a high frequencyclock and a mode for making it operative by a low frequency clock aremade to correspond to the main chip and the sub-chip, respectively, or acase where a local power source in the predetermined chip is saved andthe mode for making the chip operative by small electric powerconsumption is made to correspond to the sub-chip.

[0199] A construction of data processing programs which can be read outby the image forming apparatus according to the invention will bedescribed hereinbelow with reference to a memory map shown in FIG. 15.

[0200]FIG. 15 is a diagram for explaining the memory map in a memorymedium for storing various data processing programs which can be readout by the image forming apparatus according to the invention.

[0201] Although not shown particularly in the diagrams, there can be acase where information for managing the program group which is stored inthe memory medium, for example, version information, implementors, andthe like are also stored and information depending on the OS or the likeon the program reading side, for example, icons or the like foridentifying and displaying the programs are also stored.

[0202] Further, data depending on the various programs has also beenmanaged in the directories mentioned above. There is also a case where aprogram to install various programs into a computer or a case where ifthe program to be installed has been compressed, a program fordecompressing the compressed program and the like are stored.

[0203] The functions shown in FIGS. 11 to 14 in the embodiments can beexecuted by a host computer in accordance with the program which isinstalled from the outside. In such a case, the invention is alsoapplied to a case where an information group including the program issupplied to an output apparatus by a memory medium such as CD-ROM, flashmemory, FD, or the like or from an external memory medium via thenetwork.

[0204] As mentioned above, naturally, the objects of the invention arealso accomplished by a method whereby a memory medium in which programcodes of software for realizing the functions of the embodimentsmentioned above have been recorded is supplied to a system or anapparatus and a computer (or a CPU or an MPU) of the system or theapparatus reads out the program codes stored in the memory medium andexecutes them.

[0205] In this case, the program codes themselves read out from thememory medium realize the novel functions of the invention and thememory medium in which the program codes have been stored constructs theinvention.

[0206] As a memory medium for supplying the program codes, for example,it is possible to use a flexible disk, a hard disk, an optical disk, amagnetooptic disk, a CD-ROM, a CD-R, a magnetic tape, a non-volatilememory card, a ROM, an EEPROM, or the like.

[0207] Naturally, the invention incorporates not only a case where acomputer executes the read-out program codes, so that the functions ofthe embodiments mentioned above are realized, but also a case where anOS (Operating System) or the like which is operating on the computerexecutes a part or all of actual processes on the basis of instructionsof the program codes and the functions of the embodiments mentionedabove are realized by those processes.

[0208] Further, naturally, the invention incorporates a case where theprogram codes read out from the memory medium are written into a memoryprovided for a function expanding board inserted into a computer or afunction expanding unit connected to a computer and, thereafter, a CPUor the like provided for the function expanding board or the functionexpanding unit executes a part or all of actual processes on the basisof instructions of the program codes and the functions of theembodiments mentioned above are realized by those processes.

[0209] According to the embodiments mentioned above, even if the digitalhybrid apparatus is in the sleep mode, in the case of making a responseof the status inquired by the network, it can be responded by extremelysmall energy and at low costs.

[0210] In the power saving mode, the sub-chip meets the status requestfrom the network in place of the main chip whose electric powerconsumption is large, thereby enabling the reduction of the electricpower consumption to be realized.

[0211] Further, in the power saving mode, the main chip is set to thesleep mode, its operation is stopped, and the sub-chip recognizes itsstatus and meets the status request, thereby enabling the further smallelectric power consumption to be accomplished.

[0212] Moreover, when the status is updated in the image formingapparatus in the power saving mode, the sensor groups are classifiedinto a plurality of types, the power source is supplied only to thesensors of the necessary group (type), and the status of the imageforming apparatus is periodically updated. Therefore, the further largepower saving can be accomplished while keeping the contents which arenotified to the external host computer so as to be similar to thecontents which are obtained in the case where the power source issupplied to the sensors to which the power supply is unnecessary.

[0213] Since the status is periodically updated in the image formingapparatus under the non-wasteful power control as mentioned above, theuser who operates the external host computer can obtain the lateststatus of the image forming apparatus or the status near it withoutparticularly being aware of anything by the operation similar to that inthe case where the image forming apparatus is operating, especially,without executing any surplus operations.

[0214] If the command of the print request or the like is received inthe power saving mode and it is necessary to return the digital hybridapparatus to the normal mode, the sub-chip discriminates it, activatesthe main chip, and transfers the command information such as a printrequest or the like received by the sub-chip to the main chip, therebyrealizing the low electric power consumption while making a commandresponse on the network without interruption.

[0215] The invention is not limited to the foregoing embodiments butmany various modifications are possible on the basis of the spirit ofthe invention and they are not excluded from the purview of theinvention.

[0216] As described above, according to the invention, in the imageforming apparatus which can be connected to the network via the networkconnecting means, the further larger electric power saving than theconventional one is realized and a response of the updated status can bemade to the status request from the external apparatus.

[0217] In the image forming apparatus having a plurality of varioussensors, the status response to the external apparatus can be made tothe sub-CPU whose electric power consumption is smaller than that of themain chip.

What is claimed is:
 1. An image forming apparatus which can communicatewith an external apparatus via network connecting means, comprising:control means for, upon status updating, periodically controlling powersupply of a power source which has been saved in a power saving mode andis necessary for the status updating; and notifying means for notifyingsaid external apparatus of the status updated in accordance with thepower control of said control means.
 2. An apparatus according to claim1, wherein said control means controls so as to save the power sourcenecessary for said status updating after completion of said statusupdating.
 3. An apparatus according to claim 1, further comprising firstdetecting means and second detecting means each for detecting a statusof said image forming apparatus, and wherein said control means controlspower supply to said second detecting means in accordance with adetection result obtained from said first detecting means in accordancewith power supply to said first detecting means.
 4. An image formingapparatus which has a power control mode for shifting said apparatus toa power saving mode in which electric power consumption is smaller thanthat in a normal standby mode and can be connected to a network vianetwork connecting means, comprising: detecting means for detecting astatus of said image forming apparatus; first control means forcontrolling in a manner such that when said power control mode is saidnormal standby mode, if there is an inquiry about the status of saidimage forming apparatus from said network connecting means, informationindicative of the status detected by said detecting means is notified;update control means for intermittently supplying a power source to saiddetecting means, thereby allowing said detecting means to update thestatus; second control means for controlling in a manner such that whensaid power control mode is said power saving mode, if there is theinquiry about the status of said image forming apparatus from saidnetwork connecting means, the notification based on the statusinformation updated by said update control means is made; and powercontrol means for controlling a power supplying mode for each of saidfirst and second control means in accordance with whether said powercontrol mode is said normal standby mode or said power saving mode. 5.An apparatus according to claim 4, further comprising: status signalswitching means for connecting the status from said detecting means tosaid first control means in said normal standby mode and connecting thestatus from said detecting means to said second control means in saidpower saving mode; and network switching means for making switchingcontrol in a manner such that, in said normal standby mode, said networkconnecting means is connected to said first control means and transmitsand receives information and, in said power saving mode, said networkconnecting means is connected to said second control means and transmitsand receives information.
 6. An apparatus according to claim 4, whereina plurality of types of detecting means including at least firstdetecting means and second detecting means are included in saiddetecting means, said update control means controls power supply of apower source to said second detecting means on the basis of a detectionresult of said first detecting means according to the intermittentsupply of said power source, and said second control means controls soas to make a notification based on detection results of said firstdetecting means and/or said second detecting means.
 7. An apparatusaccording to claim 6, wherein said first detecting means periodicallyexecutes the detection during the operation of said image formingapparatus and in the power saving mode, and said second detecting meansexecutes the detection in the case where it is determined that thedetection is necessary in accordance with the detection results of saidfirst detecting means during the operation or in said power saving mode.8. An apparatus according to claim 6, further comprising third detectingmeans which does not execute the detection in said power saving mode. 9.An apparatus according to claim 4, wherein said power control meansstops the power supply to said first control means and supplies theelectric power to said second control means in said power saving mode.10. An apparatus according to claim 4, wherein when a predetermined jobrequest is received from said network connecting means in said powersaving mode, said second control means outputs a request for restartingthe operation of said first control means to said first control meansand notifies said first control means of a command based on saidpredetermined job request from said network connecting means.
 11. Anapparatus according to claim 10, wherein said predetermined job requestincludes a print job request and a facsimile job request from saidnetwork connecting means.
 12. A power control method in an image formingapparatus which can communicate with an external apparatus via networkconnecting means, comprising: a control step of, upon status updating,periodically controlling power supply of a power source which has beensaved in a power saving mode and is necessary for the status updating;and a notifying step of notifying said external apparatus of the statusupdated in accordance with the power control in said control step.
 13. Amethod according to claim 12, wherein in said control step, control ismade so as to save the power source necessary for said status updatingafter completion of said status updating.
 14. A method according toclaim 12, further comprising: a first detecting step by first detectingmeans provided for said image forming apparatus; and a second detectingstep by second detecting means provided for said image formingapparatus, and wherein in said control step, power supply to said seconddetecting means is controlled in accordance with a detection resultobtained by said first detecting step in accordance with power supply tosaid first detecting means.
 15. A power control method in an imageforming apparatus which has a controller with which first control meansand second control means can communicate, has a power control mode forshifting said apparatus to a power saving mode in which electric powerconsumption is smaller than that in a normal standby mode, and can beconnected to a network via network connecting means, comprising: adetecting step of detecting a status of said image forming apparatus; afirst notifying step of controlling in a manner such that when saidpower control mode is said normal standby mode, if there is an inquiryabout the status of said image forming apparatus from said networkconnecting means, information indicative of the status detected in saiddetecting step is notified by said first control means; an updating stepof intermittently supplying a power source to said detecting step andactivating said detecting step, thereby allowing the status to beupdated; a second notifying step of controlling in a manner such thatwhen said power control mode is said power saving mode, if there is theinquiry about the status of said image forming apparatus from saidnetwork connecting means, the notification based on the statusinformation updated in said updating step is made by said second controlmeans; and a power control step of controlling a power supplying modefor each of said first and second control means in accordance withwhether said power control mode is said normal standby mode or saidpower saving mode.
 16. A method according to claim 15, wherein saidpower control step further comprises: a status signal switching step ofnotifying said first control means of the status from said detectingstep in said normal standby mode and notifying said second control meansof the status from said detecting step in said power saving mode; and anetwork switching step of making switching control in a manner suchthat, in said normal standby mode, said network connecting means isconnected to said first control means and transmits and receivesinformation and, in said power saving mode, said network connectingmeans is connected to said second control means and transmits andreceives information.
 17. A method according to claim 15, wherein insaid detecting step, the detection by a plurality of types of detectingmeans including at least first detecting means and second detectingmeans is made, in said updating step, power supply of a power source tosaid second detecting means is controlled on the basis of a detectionresult of said first detecting means, and in said second notifying step,a notification based on detection results of said first detecting meansand/or said second detecting means is made.
 18. A method according toclaim 17, wherein in said detecting step, the detection by said firstdetecting means is periodically executed during the operation of saidimage forming apparatus and in the power saving mode, and the detectionby said second detecting means is executed in the case where it isdetermined that the detection is necessary in accordance with thedetection results of said first detecting means during the operation orin said power saving mode.
 19. A method according to claim 17, whereinin said detecting step, detection by third detecting means which doesnot execute the detection in said power saving mode is executed duringthe operation of said image forming apparatus.
 20. A method according toclaim 15, wherein in said power control step, the power supply to saidfirst control means is stopped and the electric power is supplied tosaid second control means in said power saving mode.
 21. A methodaccording to claim 15, wherein in said power control step, when apredetermined job request is received from said network connecting meansby said second control means in said power saving mode, a request forrestarting the operation of said first control means is outputted tosaid first control means and said first control means is notified of acommand based on said predetermined job request from said networkconnecting means.
 22. A method according to claim 21, wherein saidpredetermined job request includes a print job request and a facsimilejob request from said network connecting means.